Merge Request Jenkins Race Condition

Summary

There is a race condition when Only allow merge requests to be merged if the pipeline succeeds is set for a project with Jenkins integrations. Merges are allowed after a push to gitlab but before the Jenkins pipeline has started (it usually takes 30ish seconds for our build to get running on an executor). This allows users to merge untested code. This issue was also reported a year agon on the ce tracker (https://gitlab.com/gitlab-org/gitlab-ce/issues/45775)

Steps to reproduce

  1. Set up a project with Gitlab-Jenkins integration using webhooks
  2. Set Only allow merge requests to be merged if the pipeline succeeds in the project configuration
  3. Create a feature branch off of master
  4. Create a merge request to merge the feature branch into master
  5. Push a commit to the feature branch in Gitlab
  6. Immediately after pushing hit the 'merge' button to merge the feature branch into master without running the tests

What is the current bug behavior?

Users can merge code to a project with the Only allow merge requests to be merged if the pipeline succeeds before the Jenkins pipeline has started

What is the expected correct behavior?

Users cannot merge code to a project with the Only allow merge requests to be merged if the pipeline succeeds before the Jenkins pipeline has started

Results of GitLab environment info

Expand for output related to GitLab environment info 
$ sudo gitlab-rake gitlab:env:info

System information
System:		CentOS 7.3.1611
Proxy:		no
Current User:	git
Using RVM:	no
Ruby Version:	2.4.4p296
Gem Version:	2.7.6
Bundler Version:1.16.2
Rake Version:	12.3.1
Redis Version:	3.2.11
Git Version:	2.17.1
Sidekiq Version:5.1.3
Go Version:	unknown


GitLab information
Version:	11.0.4-ee
Revision:	3350cd6
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
DB Version:	9.6.8
URL:		[REDACTED]
HTTP Clone URL:	[REDACTED]
SSH Clone URL:	[REDACTED]
Elasticsearch:	no
Geo:		no
Using LDAP:	yes
Using Omniauth:	no


GitLab Shell
Version:	7.1.4
Repository storage paths:
default: 	/var/opt/gitlab/git-data/repositories
Hooks:		/opt/gitlab/embedded/service/gitlab-shell/hooks
Git:		/opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check 
$ sudo gitlab-rake gitlab:check SANITIZE=true
Checking GitLab Shell ...

GitLab Shell version >= 7.1.4 ? ... OK (7.1.4)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:root, or git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ...
5/1 ... ok
9/3 ... ok
9/6 ... ok
9/7 ... ok
9/8 ... ok
5/9 ... ok
9/10 ... ok
4/11 ... ok
9/14 ... ok
5/15 ... ok
36/17 ... ok
20/19 ... ok
20/20 ... ok
41/25 ... ok
5/27 ... ok
9/28 ... ok
5/29 ... ok
6/30 ... ok
5/33 ... ok
5/34 ... ok
20/35 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK


Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful


Checking GitLab Shell ... Finished


Checking Sidekiq ...


Running? ... yes
Number of Sidekiq processes ... 1


Checking Sidekiq ... Finished


Reply by email is disabled in config/gitlab.yml
Checking LDAP ...


Server: [REDACTED]
LDAP authentication... Success
LDAP users with access to your GitLab server (only showing the first 100 results)
[REDACTED]
Checking LDAP ... Finished


Checking GitLab ...


Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
5/1 ... yes
9/3 ... yes
9/6 ... yes
9/7 ... yes
9/8 ... yes
5/9 ... yes
9/10 ... yes
4/11 ... yes
9/14 ... yes
5/15 ... yes
36/17 ... yes
20/19 ... yes
20/20 ... yes
41/25 ... yes
5/27 ... yes
9/28 ... yes
5/29 ... yes
6/30 ... yes
5/33 ... yes
5/34 ... yes
20/35 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.4.4)
Git version >= 2.9.5 ? ... yes (2.17.1)
Git user has default SSH configuration? ... yes
Active users: ... [REDACTED]
Elasticsearch version 5.1 - 5.5? ... skipped (elasticsearch is disabled)


Checking GitLab ... Finished

merge requests ~bug ~P3 ~S3 devopsverify Verify

Edited by Elias Carter